The severing of pipes or tubes of various sizes to achieve a desired length thereof has been widely practiced by a variety of means and methods. Major problems faced by any severing technique involve the unwanted formation of burrs and/or tube deformations adjacent the severed end. Both of these results are unacceptable to achieving a uniform severed product. Any such burr has to be removed by one or more additional manufacturing steps, which adds to the time and expense of the severing operation. Similarly, a deformed end typically means that the hollow portion at the end of the severed tube must be reamed to provide a hollow portion at the end of the severed tube that is uniform with the remaining inside portions of the tube.
A number of different mechanisms have been advanced for severing tubes while still providing a uniform cut. In U.S. Pat. No. 3,613,489 to Randich, issued Oct. 19, 1971 and entitled "Method and Apparatus for Severing Tubes," the severing of tubes and pipes is accomplished by scoring the entire circumference of the fixedly held pipe or tube. The avoidance of burrs is purportedly achieved by clamping the tube in a manner that exerts a tensile stress in a direction along the axis of the tube. This patent describes the use of a plurality of blades located about the circumference of the tube to be severed. A wedging action about the circumference of the tube is used to hold it in place. U.S. Pat. No. 3,739,666 to Wright et al. issued Jan. 17, 1972 and entitled "Tube Cutting Head Structure" also describes a severing operation by cutting a tube about its circumference. In controllably positioning a cutting member relative to the tube, a weight and a counterweight are employed. Springs exert a yielding force against a cutter support opposing movement of the cutter support by centrifugal force. Movement of the cutter support by the springs is limited by engagement of ends of slots with studs. Additionally, an adjustable stop means is provided to limit movement of the cutter towards the axis of the tube, which adjustable stop means is in the form of a screw. In U.S. Pat. No. 4,633,695 to Klein issued Jan. 6, 1987 and entitled "Tool for Separation of Tubes," a machine is disclosed that separates tubes using deformation without cutting and then a subsequent cutting step is employed.
A number of devices have also been advanced for cutting a non-metallic piece while simultaneously applying tension to facilitate the cutting operation. U.S. Pat. No. 3,978,747 to Lyon issued Sep. 7, 1976 and entitled "Method and Apparatus for Severing Reinforced Elastomeric Tubular Particles" describes a cutting edge that enters a tube at one part of the tube's circumference and cuts straight through the tube without scoring the entire periphery of the tube while a mechanism pulls on the tube to create tension. In U.S. Pat. No. 4,567,795 to Pool issued Feb. 4, 1986 and entitled "Slot Cutting Apparatus," an apparatus is disclosed including a plurality of saw blades, each of which cuts a tube at one part of the tube's circumference. Tension is applied by pushing on the tube to be cut.
Despite numerous efforts to develop a satisfactory machine for severing tubes or pipes, it would be advantageous to provide an apparatus for efficiently severing a workpiece without creating burrs and without the need to subsequently ream the end of a severed workpiece so that the opening at the end is equivalent to the cylindrical bore or hollow portions within the workpiece.